U.S. CORPS OF ENGINEERS LEVEE PROJECTS IN ST. CHARLES PARISH

Donaldsonvile to the Gulf • West Bank & Vicinity Project

Click on the map to go to the Corp's pages on the Donaldsonville to the Gulf Project

Official Project Name
Donaldsonville, Louisiana to the Gulf of Mexico, Flood Control, Mississippi River & Tributaries

Location
The study area is located in southeast Louisiana and includes portions of the Parishes of Ascension, Assumption, St. James, St. John the Baptist, Lafourche, St. Charles, Jefferson, Orleans, and Plaquemines. The area is bounded on the west by Bayou Lafourche and on the east and north by the west bank Mississippi River levee, from Donaldsonville, LA to the Gulf of Mexico.

Purpose
The project purpose is to provide flood control, navigation, wetland conservation and restoration, wildlife habitat, commercial and recreational fishing, prevent salt water intrusion and promote fresh water and sediment diversion, and other purposes in the area between Bayou Lafourche and the Mississippi River System, from Donaldsonville, to the Gulf of Mexico..

Background
The non-Federal Sponsors for the study are the Louisiana Department of Transportation and Development and the Lafourche Basin Levee District.

The study area is within the Louisiana Coastal Protection Restoration Project, (LACPR). Donaldsonville field data, maps, and analyses, were used for the LACPR Project.

The study area is particularly prone to flooding by hurricane and tropical storm surges from the Gulf of Mexico. Approximately 347,000 residents and 116,000 housing units (1999 data) are at risk of flooding from a major hurricane event. Since 1985, FEMA has declared six Federal Disasters within the study area due to flooding. The most recent disaster declaration was in 2005. Storms in 1959, 1989, 1991, and Hurricane Juan in 1985 produced near-100-year flood conditions. Tidal and hurricane surges reduce the basin’s capacity to accommodate heavy rainfall events. Flood damages are increased by the long duration of high stages due to conveyance restrictions, high tides, land subsidence, and sea level rise.

Five and possibly six hurricane risk reduction systems and coastal restoration systems are being studied to protect the area between Bayou Lafourche and the Mississippi River. Many people have expressed interest and support for the Gulf Intracoastal Waterway (GIWW) hurricane levee system. This system provides multiple lines of hurricane protection when combined with existing levees. Multiple levels of storm protection are consistent with the Dutch approach to prevent damage to life and property. A very brief description of the Dutch Flood Control Standards are presented in the Reports/Presentation tab. This alignment also eliminates the need for a structure at Larose and the GIWW that is to be constructed by the Morganza to the Gulf project. The structure is not required since the levee would prevent surges from entering the GIWW and proceeding to the Morganza to the Gulf protected area. One, or two flood control structures will be required to keep gulf surges from entering the protected area through existing navigable waterways. The Ridge alignment (formely the Bayou Lafourche Levee Alignment) is a unique alignment that allows tidal surges into the basin. The hurricane levee system would be constructed along the wetland/farmland interface and terminates where the tidal surge ends. Proponents of this levee system believe that it poses less of a direct impact on the marsh, maintains tidal connectivity, and reduces developmental pressure. Most of the hurricane levee systems that are being studied will protect US 90 and LA 308, the two major hurricane evacuation routes.

Interior drainage capacity and demand are being analyzed to determine what improvements are required. Portions of the study area are in desperate need of environmental restoration. A system-wide modelling effort to determine the influence of rainfall events, small freshwater diversions, salinity intrusion, and sediment patterns is underway. Specific details about the alternatives that are being studied are presented in the Study Features document in the Reports/Presentation tab.

Authority
The study was authorized by a resolution adopted by the Committee on Transportation and Infrastructure of the United States House of Representatives on May 6,1998.

Scope
The scope is to study various alternatives that will provide flood protection from tidal, hurricane surges, and heavy rainfall events. Determine the adequacy of the existing interior drainage systems and evaluate whether additional pumping capacity is required. Aanalyze recreational, cultural, and environmental needs. Refer to the Data Sheet in the Reports Tab for a comparison of the hurricane levee systems and coastal restoration measures that are being studied.

Progress to Date
We have completed a major milestone recently, the completion of the hurricane models.

A Feasibility Cost Sharing Agreement was signed in February 2002 with the Louisiana Department of Transportation and Development and the Lafourche Basin Levee District. The draft report is expected to be completed at the end of 2008. The hydraulic analyses to determine the hurricane levee heights are complete and the results will be reviewed by the Independent Technical Review and Peer Review teams. The interior drainage, salinity, and sediment analyses for the existing and future conditions are ongoing. Designers have completed the analysis that determined the hurricane levee heights for various storm events, width and number of gates and openings that are required in each hurricane levee systems for navigation and environmental purposes. In the early part of November 2007, the Sponsors awarded a contract for geotechnical, levee, and structure designs. Currently, we are focusing on environmental measues for the entire basin and on the economic analyses. When a hurricane levee system is selected, public meetings will be scheduled throughout the study area to inform the public, public officials, and special interest groups about the results of the investigation to date.

Financial Status
No Information at this time.

Official Project Name
West Bank and Vicinity Project

Click on the pictures to open a larger map
Western Tie-In Alignment I	Western Tie-In Alignment II	Western Tie-In Alignment III

Click here to view a PDF document discussing the status of in-progress and proposed alternatives that will reduce risk to the communities in the Westbank and Vicinity portion of the Greater New Orleans Hurricane and Storm Damage Risk Reduction System in St. Charles and Jefferson
parishes.